Finned typed heat exchangers are commonly used in a variety of heat exchanger-type apparatus. Finned heat exchangers having a tube bundle of a serpentine arrangement and fins between the tubes are used in condensers and evaporators of refrigeration units, air conditioning units and the like.
The standard form of evaporator used in refrigerators involves the use of a serpentine-type tube bundle having a plurality of fins extending perpendicular to the tubes. The fins are planar and usually have a thickness of approximately 0.25 millimeters. Efforts have been made in the past to improve the efficiency of this standard type of evaporator and condensers used in refrigeration devices. U.S. Pat. No. 1,773,249 discloses a condenser arrangement having fins with a plurality of transverse corrugations formed therein. When the fins are assembled and the corrugated portions interconnected, spaces between the fins are defined through which air may flow. Another form of corrugation in thick fins to induce turbulence in the flow of air over the fins of the heat exchanger is disclosed in U.S. Pat. No. 3,645,330. The fins include corrugations which extend transversely of each fin. The fins are all interconnected by collars which are, in turn, welded to the tubes of the coil carrying the medium to be heat exchanged. The corrugations in the fins serve to break up the boundary layer of air flowing over the thick fins.
Further improvements in the fin construction involve the use of apertures in conjunction with corrugations in the tubes, such as disclosed in U.S. Pat. Nos. 3,796,258, 4,365,667 and 3,397,741. The openings in the fins, aside from those openings which receive the tubes of the heat exchanger coil, function as louvres to deflect the flow of air through the fins to enhance heat transfer from the fins to the flowing medium.
All of these forms of heat exchangers involve the use of plate fins which have a thickness normally in the range of 0.25 millimeters or greater. With the increased costs involved in materials of constructions for heat exchangers, there is a need to reduce the amount of materials in the heat exchanger yet maintain or improve its operating characteristics.